.Gob file-Gob file is paced in Data folder of C07 root directory as data.gob. It mostly contains all the stuffs from where user edits it. It can be open with biggui and then you can export any file from it and edit it.

.fsh files-It contains graphics of overlays, faces, bats, stadium etc. It can be edit by FshEditor

.o files-It contains 3d models, mostly for faces and stadiums. It can be edit by o-edit

.ash files- It contains the Ashes 2005 scenarios. It can easily edit by notepad or wordpad.
.rsg files- It contains fixtures of tournaments like World Cup, Domestic tournaments. Easily edited by notepad or wordpad.

.cfg files- Configuration files mostly used for gameplay. It also can be edited by notepad or wordpad.

.xml files- These are used in many places in C07. It contains info about stadiums, commentary, teams, gameplay, replays etc. Can be edited by notepad or wordpad.

.english file- It contains text which is used in C07 like "Play Now", "Game Modes" etc. Can be edited by any Hex editor.

.rfe files. It also used for many places. But editing these files may harm your C07. It also contains Menu overlays which can be edited by Hex Editor. But Be careful while editing.

Audio Files
All the these files can be open by can be open by biggui. It contains media files in .asf files which can be converted by Hitty Sound Editor or Ditty Importer

pbp.big- It contains commentary of C07.

Music.pbp-Contains music used in jukebox of C07.

Aems.big and ambient.big-Contains in-game sound which we hear when any match is played.

This is all which I know and can be edited. I will update this thread soon.

If you still can't understand then please read tutorials posted in C07 Tutorials forum.